This was the natural progression from Bullseye - where Jim would spend the first third of the show blethering tedious rubbish with the contestants.
Of course, this was long before the sob story had been invented(!), but somebody would mention their very dull job and Jim would ask the most boring questions ever about it.
"Aaaahhĥ, so you're a dry cleaner? And is your shop in Preston itself, or one of the surrounding suburbs? Tell me, what kind of chemical formula do you mostly use in the process? Oh, I see - and how many bottles would you usually get through in a week? Do you charge an extra supplement for suede or leather? And do you open late on Thursdays?"
When people could simply take no more job-based tedium, but there were still 7 minutes of air time to fill, the sob story was born!
I always feel so sorry for contestants when they say that, if they win, they want to splash out on the fancy car or world cruise that they've always dreamed of; then the next contestant says that they need the money to pay for a life-saving operation or to give to their local hospice, and thus they totally wee in the first person's chips on national TV.
And the people who say they want to give SOME of the tens-of-thousands prize money to a worthy cause that's so very dear to them. How much? Three quarters? Half? 10%? We all know that a tenner would just as much count as 'some', if that's your little ploy!